Carburetor device



July 23, 1940. H. w. FARR 2,208,864

CARBURETOR DEVICE Filed Dec. 16, 1937 Inventor #62723 )44 Farr By $5M ER fll'l'orney Patented July23, 1940;

UNITED ST ATES caaauaa'ron. DEVICE Henry W. Farr, Royal Oak, Mich, assignor to- Carter Carburetor Corporation, St. Louis, Mo., a corporation of Delaware Application December 16,1937, Serial No. 180,107

3 Claims. (01. 2 1-41) This invention relates to carburetors for internal combustion engines and consists particularly in novel means for adjusting the fuel mixture supplied by the carburetor, particularly when the associated engine is being used as a brake.

Many automobile drivers frequently coast with the engine in gear and the throttle valve substantially closed so that the engine functions as l a brake tending to slow down the vehicle. Un-

der these conditions the carburetor idling and low speed system is exposed to abnormally high suction and, in some cases, the fuel supplied is not adequate to maintain even running of the engine, due to the restrictions in the system, with the result that the engine audibly misses and pops" or sputters. I have found that by enriching the mixture supplied when the idling ports are exposed to such abnormally high suc- 80 tions, smooth, quiet running of the engine can be maintained.

Accordingly, an object of the present invention, is to provide means for enriching the fuel mixture supplied by the idling system when the 25 suction applied thereto exceeds normal idlin suction.

This object and other more detailed objects hereafter appearing are attained by the structure illustrated in the accompanying drawing in 80 which:

Fig. 1 15's. vertical sectional view of a carburetor embodying the invention, and

Fig. 2 is an enlarged view of a portion of the structure in Fig. 1.

38 The carburetor shown in Fig. 1 comprises a downdraft mixture conduit including air horn I, venturis 2, mixing chamber 3, and outlet portion 4, flanged as at 5 for attachment to the intake manifold (not shown) of an associated in- 40 ternal combustion engine. The usual choke valve 6 and throttle valve I are pivotally mounted within the mixture conduit and provided with any suitable operating mechanism. Adjacent the mixture conduit is a constant level chamber 8 from which fuel is supplied by suction to the mixture conduit through main fuel nozzle 9 and anidling system including passages III, III and H, the latter discharging through a port I! adjacent the edge of throttle valve 1 when closed, and additional passage ports I3 and I. An air bleed is provided at l5 so that a rich emulsion of air and vaporized fuel is supplied through the idling ports, this being added to air which passes 5 around the throttle valve through upper port I! when the throttle is closed'to provide the proper idling mixture.

Port I8 is also disposed to discharge idling mixture into the mixing conduit beneath the throttle and is controlled by a needle valve Ii 6 forming the inner end of a screw I I having a kerfed head l8 accessible from outside the carburetor body for adjusting the idling mixture.

A vertical passage H extends downwardly from passage ll through flange 5 and connects pasl0 sage II with the lowest idling port l4. Passage ll threadedly mounts a threaded, hollow valve housing l8, enclosing a ball valve l9 yieldingly urged against valve seating shoulder near the upper end of housing l8 by a coiled spring 2t. 15 Spring 2l seats, at its lower end, on a plate 22 carried in groove 23 at the bottom of valve housing [8. The valve housing has central openings 24 in the wall thereof providing communication between port passage [4 and the interior of the 20 housing. Thus ball valve I9 controls communication between idling passage and port It and is exposed through port [4 and opening 24 to the suction in the mixture conduit posterior to the throttle valve. 25

Spring 2| is suficiently strong to maintain ball valve is against its seat at all times during normal operation of the carburetor, that is, when the suction applied to the ballvalve is not in excess of the normal idling suction which ordinarily, corresponds with a manometer reading of 17 or 18 inches of mercury. When the associated engine is being operated by a force other than the explosion in its firing chamber, that is, when the engine is being used as a brake, the suction posterior to the throttle valve substantially exceeds normal idling suction and may reach as much as 24 inches of mercury. Under such conditions, ball ill will be unseated, permitting the discharge into the mixture conduit of additional rich mixture supplied through passage II. This has the effect of substantially enriching the total idling mixture, including air sup-' plied through air bleed I 5 and port l2 around .the edge of the throttle valve and fuel supplied through passages "I,- III and H.

. The fuel discharge means, including the idling system as shown in the drawing, is in general well known in the art and these features may be modified as desired. The structure illustrated may be modified in other respects, as will occur to those skilled in the art, and the exclusive use of all such modifications ascome within the scope I of the appended claims is contemplated.

I claim: ll

in, an idling passage including port means for discharging fuel into said conduit during idling and part throttle operation 0! the carburetor, a suction-operated valve in said passage, and means for maintaining said valve closed during normal idling operation said means being adapted to yield when said valve is exposed to greater than idling suction to increase the fuel discharged by said passage.

3. In a carburetor for an internal combustion engine, a mixture conduit, a throttle valve therein, an idling system for supplying iuel to said conduit when said valve is closed, said system communicating with said conduit through port means, and a suction operated valve in said system adjacent said port means and constructed and arranged to open only when greater than normal idling suction is applied to said port means to increase the fuel supplied by said system.

HENRY W. FARR. 

